The well known method of silver salt photography generally comprises forming a colored image by developing exposed silver halide grains with a primary aromatic amine compound as a developing agent, reacting a color coupler with the oxidized form of a developing agent thereby formed, subjecting the material to a bleaching process (bleaching, fixing and/or bleach-fixing), a water washing process and/or a stabilizing process and drying.
There is a need in the art to conduct development processing of a photographic material as rapidly as possible to improve the productivity of the processing house and to shorten the time for which the customer must wait to receive the processed prints.
Increasing the processing temperature and increasing the replenishment rate are generally used as methods of shortening the time of each processing operation, but many other methods such as the use of forced agitation and the addition of various accelerators have also been suggested.
For example, a method in which a color photographic material containing a high silver chloride content emulsion in place of a conventionally employed silver bromide or silver iodide emulsion is processed to speed up color development and/or to reduce the replenishment rate has been disclosed in International Patent(Laid Open) WO 87-04534.
By using high silver chloride content emulsions and development processing baths of this type, the 3 minute 30 second development time for a conventional silver chlorobromide emulsion system (for example, color process CP-20 of the Fuji Photo Film Co., Ltd.) has been shortened to 45 seconds (for example, color process CP-40FAS of the Fuji Photo Film Co., Ltd. total processing time: 4 minutes). However, such shortened processing times are still unsatisfactory when compared with the total processing times achieved in other recording systems (for example, electrostatic copying systems, thermal transfer systems and ink jet systems).
In view of the above, it is clear that the processing time from the bleaching process onwards must be shortened in order to effectively reduce the overall processing time in addition to providing a shortened color development processing time.
Increasing the concentration of bleaching agent in the processing bath and increasing the activity of the processing bath are effective means of achieving adequate bleaching even with short bleaching times. However, as the bleaching agent concentration is increased, it becomes increasingly difficult to remove the bleaching agent from the photosensitive material with the subsequent water washing or stabilizing process. Furthermore, some of the bleaching agent inevitably remains in the photosensitive material.
Moreover, when the processing time is shortened and the subsequent water washing or stabilizing process is also simplified and shortened, the residue of developer components and bleach-fixing components remaining in the photosensitive material, and especially bleaching component residues due to increased bleaching agent concentration, is inevitably much higher than that observed with a water washing or stabilizing process carried out with the longer conventional processing time.
It has long been known that a residue of developing components and bleach-fixing components in the photosensitive material adversely affects the storage properties of a print. Residual color developer reacts with unreacted coupler with the passage of time to result in undesirable staining. Furthermore, if bleaching components remain, the photosensitive material provides an oxidizing environment such that yellow staining occurs, especially under conditions of high temperature and humidity.
The removal of these residual reagents from photosensitive materials has been reported by H. Iwano, T. Ishikawa and M. Yoshizawa at the fifth Photofinishing Technology International Symposium (Chicago, 1986) in a report entitled The Chemistry of Washing, The Way to Ensure Photoprocessing Quality at Minilabs. It was found that the selection of an appropriate washing time, wash water temperature and agitation speed is effective for removing developing agents, and that washing with large amounts of water or in a multistage countercurrent system is effective for the removal of ethylenediaminetetraacetic acid, ferric salt widely used as a bleaching agent. It was further found that the difference in the removal rate of residual developer as compared to residual bleaching agent (due to the means of promoting the removal of developing agent and the means of promoting the removal of bleaching agent) is dependent on the extent of the interaction of these components with the binder.
It is known that in the case of rapid processing in particular the storage properties of prints which have been processed continuously are considerably degraded (in terms of increased staining and a lowering of dye density) because of the increase in residual bleaching agent concentration and the shortening of the water washing characteristic of ultra-rapid processing.
There tends to be an improvement with respect to this type of staining when a low pH of the photosensitive material is maintained. However, a low pH results in cyan and yellow color fading under conditions of high temperature and humidity. Techniques for reducing carryover or for decolorizing colored components in the photosensitive material when water washing is inadequate are proposed in JP-A-58-14834, JP-B-61-20864, JP-A-60-263939, JP-A-61-170742, JP-A-58-132743 and JP-A-61-151538 (the terms "JP-A" and "JP-B" as used herein refer to a "published unexamined Japanese patent application" and an "examined Japanese patent publication", respectively.) However, each of these techniques is inadequate for ultra-rapid processing since the water washing or stabilizing time and the amount of water used are very small. Larger amounts of developing components and bleach-fixing components are carried over as compared with conventional washing, and in those cases where continuous processing is carried out with a high bleaching agent concentration in particular, large amounts of colored components are left behind in the photosensitive material. As a result, staining tends to occur in the white portions on storing the finished print under conditions of high temperature and humidity, and fading of the dyes also tends to occur such that the commercial value of the print is reduced.
Moreover, a method in which a high silver chloride content emulsion is processed in a substantially benzyl alcohol free color developer for not more than 25 seconds and, wherein the total processing time, including the said development processing time, the bleach-fixing process time and the water washing process time, is within 2 minutes has been proposed as a technique for shortening the wet bath processing time from development to water washing as described in JP-A-1-196044. However, this technique alone is still inadequate for resolving the problems described above.